Monitoring set job telegraph repeaters



oct-

J. HERMAN MONITORING SET FOR TELEGRAPK REPEATERS 2 Sheets-Sheet 1 Filed June 1923 INVEN TOR (KM/mm 6 ATTORNEY J. HERMAN v MONITORING SET FOR TELEGRAPH REPBATERS Filed Juno 2 1923 2 Sheets-Shut 2 IN VEN TOR ATTORNEY JHarma/V Patented Oct. 27, 1925.

1.1 Mr E STATES PATENT OFFICE.

JOSEPH HERMAN, 038 NEW YORK, Y., ASSIGNOR T0 AMERICAN TELEPHONE AND TELEGRAPH COMPANY. it. CORPORATION OF NEW YORK.

MONITORING fiET 'FQR TELEGRAPH REPEATERS.

Application filed June 27, 1.923.

To all whom it may concern:

Be it known that I, Josnrn HERMAN, residing at New York, in the county of New York and State of New York, have invented certain Improvements in Monitoring Sets for Telegraph Repeaters, of which the following is a specification.

This invention relates to arrangements for monitoring on telegraph lines and more particularly for monitoring on such lines where through repeaters, having no provision for monitoring, are utilized.

The monitoring arrangements of the invention may be used to considerable advantags for observing the transmission through the repeater set and for locating faults in a line into which a number of through repeaters are connected. The arrangements of the invention furthermore provide means for sending and receiving at a point where a repeater oi this type is employed.

One of the main operating features of the arrangements of the invention consists in utilizing the relay windings in the artificial line circuit of the repeater for operating the relay so as to make the relay serve as a sending pole-changer under control of the monitoring set. Other features and advantages of the arrangements of the invent on w ll appear more fully. from the detailed description hereinafter given. In the following description the monitor ing arrangements or the invention will be disclosed in the manner in which they may be app-lied to so-called metallic polar-duplex telegraph repeaters. It should be understood, however, that this is only a particular application of the invention and that the invention may be used in connection with other types of telegraph systems. The invention may be more fully understood from the following description together with the accompanying drawing in the Figures 1, 2, 3, a, 5 and 6 of which are illustrated circuit diagrams embodying the arrangements of the invention. Fig. 1 shows in detail the circuit arrangement of a metallic polarduplex telegraph repeater set and the monitoring set of the invention. Figs. 2, 3,- 4, 5 and 6 are schematic diagrams illustrating the polarity of the telegraph currents encountered under various conditions.

In Fig. 1 is shown a west line LVV and an east line LE interconnected by a through telegraph set. Line LW is balanced by the Serial No. 648,096.

network and line LE is balanced by the network NE. The line LVV includes a relay aving the line windings 1 and the network windings :2 interconnected by the contacts of zacl: JVV, points (2 and i being connected together and points 7 and j being connected-to gcther. These relay windings normally control the pole changer apparatus TW to repeat s gnals from line Ll/V to line LE. The rind-points giand [tho-f the windings 1 and 2 are conucctec to t e pole chan in a ratus lli. Associated with the 5015 cli iigr ers TW and TE are the noise killer devices o and The line LE includes a relay hav ingthe line windings 3 and the network wind ngs tinterconnected through. the contacts of jack JE, points z" and 6 being con nected together and points; j and f bein connected together. The midapoints q and it of windings 3 and 4i are connected to the pole changer TW. The signals coming in over line LTVV operate the relay included therein which operates the pole changer TW to repeat the signals out over line LE. The signals comingin over line LE operate the relay included therein which operates the pole changer TE to repeat the signals out over line MW in a well known manner. I

The monitoring set of the invention includes the plug P which may be associated with the jacks J W or JE. Two of the sets or conductors oi"- plug P are associated with the contacts of a two position switch S. A relay 7 is provided controlled by a key K. the relay 7 has two armatures which operate between the tired contacts a, a, and b, 5. One of the sets of conductors of plug Pare connected to these armatures. A sounder 10 is provided connected to one set of conductors of plug P and a battery 9 is provided which may be associated with contacts a, a, and a, I), over the contacts of switch S.

When plug P is inserted in jack J W, with key K closed, and the switch S is on its normal position the line windings 1 will be connected to the network windings 2 and service may take place between LW and LE in the normal manner. Points 2 and 7 will be connected with points z" and over the following circuit; over contacts of jack JW and plug P, conductors 11, contact of switch S, conductors 14, contacts of switch S, conductors 15, contacts a, a and over conductors 13 to points i and j. The pole changer TE is connected to points 9 and k. which are connected over conductors 12 and the contacts of switch S to the last mentioned circuit and accordingly service may take place between line LE and line LVJ in the normal manner. The sounder 10 is bridged across the contacts oi switch included in the above circuits and accordingly the trans mission from LE to LlV may be observed.

lVhen both the east line and west line subscribers have their keys closed the current in the line will be zero as the battery potentials at the ends of the line oppose each other. 'Such a condition is illustrated schematically in Fig. 2, the condition of no current being indicated by showing the line and line windings as dotted lines. It will be seen how ver that current from the local batteries will flow through the network windings as indicated by the arrows and will tend to hold the armature of the pole changer in one direction. It" the monitoring operator now desires to send to the east line LE the key K will be opened. This will operate relay 7 which will cause its armatures to move over to the contacts I), b. The contacts are connected over conductors 16, contacts of switch S. and conductors 17 to the battery 9 and have a polarity normally opposite to contacts a, a. Accordingly the operation of key K and relay 7 will reverse the polarity of the current supplied over conductors 13 to the network windings 2 and cause the armature of the sender TVV to change its position thereby transmitting signals over line LE. Such a condition is shown schematically in Fig. the heavy arrows showing the direction of the normal current and the dc ted arrows showing the direction oi the current to be reversed upon the operation of key K. it will be noted that the operation of key K will. have no effect on the line, such as Liv. and accordingly will not effect the west subscriber under these conditions.

If the east subscriber opens his key to break the sender the local transmitter will reverse the polarity of the contacts a, a, and they will now be of the same polarity as contacts k). Accordingly, any operation oi key K and relay '2' will only serve to send current through the network windings in one direction and will not operate the transmitter TW. Such a condition is illustrated in Fig. 6, it being pointed out that under these conditions the dotted arrows and heavy arrows which indicate the current in the network windings will for both operations of the key K be. in the same direction. The condition of the line when the east subscriber opens his key is illustrated schematically in Fig. 4.

\Vhen the monitoring set is connected with jack J W the west subscriber hears only the message coming from the east line and does not hear the monitoring operator.

However, the west subscriber may interrupt both the east subscriber and the monitoring station by opening his key. The condition of the line currents when the west subscriber opens his key is shown schematically in Fig. 11. Such interruption can be remedied by throwing the switch to the left or oii' position. This will remove the network windings 2 from the line windings 1 and connect the network windings to conductors l7 and the metallic battery 9 over the contacts of switch 5 during the marking or closed position or the monitoring key K. There is thereforeno danger of the west relay operating when the east subscriber sends even though the west line balance has been destroyed. This is true because the artificial line windings 2 will be disconnected from the line windings 1. and connected to the battery 9 of fixed polarity while receiving signals.

To send from the nonitoring station out ever the west line LVV the plug P would connected to jack 5E. The operation would then be substantially similar to that already given.

vVhile the invention has been disclosed in certain specific arrangements which are deemed desirable, it is understood that it. is capable of embodiment in many and widely varied forms as defined by the appended claims.

VVhat is claimed is:

1. A. transmission line including two line sections interconnected by a telegraph repeater, said telegraph repeater including line windings and balancing network windings in etch e section. poi-e cl =.ngcrs coni'iccted to the midpoints of said windings, the pole changers connected to the midpoints oil the windings in one line section being controller by the windings in the other line section, and switching means connected to each set of said windings and their midpoints, and n'ionitoring apparatus including switching means adapted to be connected to either of said last mentioned switching means, and means associated with said switching means "for reversing the polarity of the current normally applied to the network windings oi the set.

2. A transmission line including two line sections interconnected by a telegraph repeater, said telegraph repeater including line windings, and balancing network windings in each line section, pole changers connected to the inidpoints of said windings, the pole changers connected to the midpoints ot the windings in one line section being controlled by the windings in the other line section, and switching means connected to each set of said w ndings and their midpoints, and monitoring apparatus including switching means adapted to be connected to either of said last mentioned switching means, and

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means associated with said switching means for reversing the polarity of the current normally applied to the network windings of the set without disturbing the electrical condition of the line windings of the set.

3. A transmission line including two line sections interconnected by a telegraph repeater, said telegraph repeater including a set of line windings and network windings in each line section, pole changers connected to the midpoints of said windings, the pole changer connected to the midpoints of the windings in one line section being controlled by the windings in the other line section, and switching means connected to each set of said windings and their midpoints, and monitoring apparatus including switching means adapted to be connected to either of said last mentioned switching means, circuit arrangements connected with said switching means whereby the line windings and network windings may be connected together and the pole changer may be connected to their midpoints at points in said circuit arrangements in said monitoring apparatus, and receiving apparatus connected to said last mentioned points.

4. A transmission line including two line sections interconnected by a telegraph repeater, said telegraph repeater including a set of line windings and network windings in each line section, pole changers connected to the midpoints of said windings, the pole changer connected to the midpoints of the windings in one line section being controlled by the windings in the other line section, and switching means connected to each set of said windings and their midpoints, and monitoring a paratus including switching means adapted to be connected to either of said last mentioned switching means, circuit arrangements connected with said switching means whereby the line windings and network windings may be connected together and the pole changer may be connected to their midpoints at points in said circuit arrangements in said monitoring apparatus, and means connected to said circuit arrangements for reversing the polarity of the current normally applied to the network windings.

5. A transmission line including two lin sections interconnected by a telegraph repeater, said telegraph repeater including a set of line windings and network windings in each line section, pole changers connected to the midpoints of said windings, the pole changer connected to the midpoints of the windings in one line section being controlled by the windings in the other line section, and means connected to the network windings of; at least one of said line sections for reversing the polarity of the current normally applied to said network windings and for simultaneously maintaining the normal electrical condition of the line windings oi the set. 1

6. A transmission line including two line sections interconnected by a. telegraph repeater, said telegraph repeater including a set of line windings and network windings in each line section, pole changers connected to the midpoints of said windings, the pole changer connected to the midpoints of the windings in one line section being controlled by the windings in the other line section, and switching means connected to each set of said windings and their midpoints, and monitoring apparatus including switching means adapted to be connected to either of said last mentioned switching means, circuit arrangements connected with said switching means whereby the line windings and network windings maybe connected together and the pole changer may be connected to their midpoints at points in said circuit arrangements in said monitoring apparatus, and a two position switch associated with said circuit arrangements in said monitoring apparatus whereby said network windings may be disconnected from said line windings and may be connected to a battery of fixed polarity.

In testimony whereof, I have signed my name to this specification this 26th day of June, 1923.

JOSEPH HERMAN. 

